"Unless your righteousness exceeds that of the scribes and the Pharisees, you will never enter the kingdom of heaven." The problem is that our righteousness is that of the scribes and the Pharisees. Our righteousness is the same as the scribes and the Pharisees. To prove this our Lord points us to our anger. Anger and indignation is the by product of having been sinned against. But what we do with that anger is more telling. It reveals how we view ourselves, and how we view our neighbor. When we are angry, we assume that we are in the right and they are in the wrong. And when we have been sinned against, our brother is in the wrong. That does not, however, mean that we are necessarily in the right.
*The problem with anger is that if it is not dealt with, if it is not confessed to God and to one another so that it can be taken away and cleansed from us by the blood of Jesus in Word and Sacrament, it stays with us and destroys us. Satan uses it against us. He gets us to brood over it, to replay the incident in our minds like a music track on repeat or a video loop. Repeatedly and obsessively in our minds, we stew over it with ever greater emphasis on its gravity and injustice. As our anger simmers, our remembrance and assessment of the offense is gradually distorted. And we begin to bring our mental accusations against the offender in the court of our minds. There we hold a secret trial in which we both prosecute and pass judgment on the wrongdoer. The more we stew over it, the angrier we get. And then we remember all the other offenses that we have suffered from that person and all the other people that have hurt us. And that fuels our anger and our desire for justice. We maintain that we are in the right; we are justified in our judgment of them. We hold the moral high ground against them. And before we know it, anger leads to bitterness and resentment, which in turn, leads to outrage, hatred, and lust for revenge. And so we end up stewing in our own poison. For we have begun to hate those whom we should love. We have become the scribe and the Pharisee.
This is spiritual suicide. For "you have heard that it was said to those of old, 'You shall not murder; and whoever murders will be liable to judgment.' But I say to you that everyone who is angry with his brother will be liable to judgment; whoever insults his brother will be liable to the council; and who ever says, 'You fool!' will be liable to the hell of fire." In other words, whoever is angry, stews in that anger, holds court in his mind to prosecute and pass judgment is liable to the hell of fire. Whoever does this has cut himself off from Christ. For when we hate our neighbor, seek revenge against him, we don't usually attack them physically. We do so verbally, emotionally, and spiritually. We talk to others about them to get them on our side so that they will join us in condemning them. We write them off and give them the cold shoulder. We reject them in our hearts and treat them as being dead to us. This is spiritual murder. And by cutting ourselves off from our brothers and sisters in Christ, we cut ourselves off from Christ as well. And this is spiritual suicide.* We take the position of the scribes and the Pharisees, and we follow in their righteousness. And unless your righteousness exceeds that of the scribes and the Pharisees, you will never enter the kingdom of heaven.
The only righteousness that exceeds that of the scribes and Pharisees is the righteousness of Christ. For He came not to abolish the Law and the Prophets. He came to fulfill them. By His active obedience, Christ did all that the Law and Prophets demand. By His passive obedience, He allowed the punishment for having not done what the Law and the Prophets demand to fall upon Him. He not only fulfilled the commandments in His life, but in His death fulfilled it's punishment. And He did this for you. He did it on your behalf and for your benefit. So that being joined to Him by water and Word, His righteousness is your righteousness, His status as the beloved Son of God the Father is your status as the beloved sons of God the Father, and His life sitting at the right had of the Father for all eternity is your life for all eternity.
So then, having all this, when you come together around the altar offering your gift, which is an outward display of righteousness, and there you remember that your brother has something against you, that there you remember your anger turned to hatred for your brother, which is murder and suicide, go and be reconciled to your brother. For the Lord desires mercy not sacrifice. Confess your sin to him that he may repent and confess his sin to you. And then come to the altar together not to give but to receive the gift your Father has prepared for you, that you both may be cleansed by the body and blood of Christ and live in and under the righteousness that exceeds the scribes and the Pharisees unto eternal life in the kingdom of heaven.
* This section is paraphrased and taken from John Kleinig's Grace Upon Grace, 234–235.